Wet scrubbers accomplish particulate collection by employing water or another liquid as the collection media. There are many scrubber designs, but most particulate scrubbers work by creating a wetted target for particle collection.
This wetted target plate can be a bed of water or a zone where the particle and water droplet collide. Benefits of wet scrubbers are their ability to perform in various moisture and temperature conditions, their resistance to chemical corrosion, and their low maintenance needs.
However, wet scrubbers require a significant amount of water, which must be disposed of along with the collected particulate. This lowers the collection efficiency and increases the energy costs. Settling ponds are one common method of collected particulate disposal in the mineral processing industry, and the water from these ponds can often be reused within the operation.
The air cleaning efficiency of this type of collector primarily depends on its pressure drop. Scrubbers with high differential pressures have higher air cleaning efficiencies than scrubbers with lower differential pressures.
These pressures range from 1 to over 15 inches wg. The style of scrubber chosen for a particular application depends on the air cleaning required, the dust loading, and the particle sizes involved.
Wet scrubbers are particularly advantageous when handling moist hot gases. Problems such as bag blinding and condensation can arise when fabric collectors are used to clean moist hot gases. These problems are eliminated when using scrubbers. However, wet scrubbers discharge contaminated water, which requires further treatment in a settling pond or sewage system.
Reference
NIOSH Mining Program Report of Investigations, « Dust Control Handbook for Industrial Minerals Mining and Processing» Second Edition.
